"I miss you" has not been done before but "I'll miss you" has. Please limit your posts in this thread to translations of the former, and use the other thread for translations of the latter.

"I miss you" in Arabic:

*If the speaker is a male,...

...and is speaking to one person: إني مشتاق إليك (inni mushtaaqun ilaykaa - if "you" is masculine; inni mushtaaqun ilaykii - if "you" is feminine)
...and is speaking to two people: إني مشتاق إليكما (inni mushtaaqun ilaykumaa)
...and is speaking to a group of three or more people, at least one of whom is male: إني مشتاق إليكم (inni mushtaaqun ilaykum)
...and is speaking to a group of three or more females: أني مشتاق إليكن (inni mushtaaqun ilaykunna)

*If the speaker is a female,...

...and is speaking to one person: إني مشتاقة إليك (inni mushtaaqatun ilaykaa - if "you" is masculine; inni mushtaaqun ilaykii - if "you" is feminine)
...and is speaking to two people: إني مشتاقة إليكما (inni mushtaaqatun ilaykumaa)
...and is speaking to a group of three or more people, at least one of whom is male: إني مشتاقة إليكم (inni mushtaaqatun ilaykum)
...and is speaking to a group of three or more females: أني مشتاقة إليكن (inni mushtaaqatun ilaykunna)

In Egyptian colloquial Arabic you can say:
waHishni (to a male)
waHshaani (to a female)
waHshenni (to a group of people)

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These are verbs in present tense.

Also in Egyptian colloquial Arabic, people can sometimes use the past tense to express the same meaning (I miss you) :
waHashteni (to a male)
waHashtini (to a female)
waHashtuuni (to a group of people)

In Japanese I think that it is:あなたがいなくて寂しいです。
Anataga inakute sabishii desu.

(by the way could someone please tell me what なくて means here ?)

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inakute: "as [you are] not present" from "inai", negative from of "iru" (exist, for humans).

In a romantic context, a more stronger adjective seem to be handy:
あなたが恋しいです。
anata-ga koishī desu.

The adjective koishī expresses strong disatisfaction for the absence of the person or the object referred to. It was more frequently used a generation or two ago but, nowadays, its domain seems to be restricted to romance and love affairs.

In Turkish we generally say "Seni özledim" instead of "Seni özlüyorum".
Both sentences are true, but first one is more common I think.
"Seni özledim" is not actually in present tense (gramatically in past)
but this sentence refers a present meaning in daily use.

I think you will find there is already a verrrrry long thread with "I miss you", and others with all kinds of typical things lovers like to say to eachother... I love you, I need you, kiss, etc... It's a good idea to do a search for threads like this first before opening up a new one...